Verifiable Structured Encryption

Abstract

Structured encryption schemes generalise symmetric searchable encryption (SSE) schemes by allowing encrypted search on arbitrarily structured data, instead of keyword-based search only. Both structured encryption and SSE schemes mainly consider security against passive adversaries, until recently where SSE schemes secure against active adversaries were proposed. This means in addition of querying encrypted data, the adversaries can modify encrypted data in the storage. SSE schemes secure against such adversaries are termed verifiable SSE. In this paper, we examine verifiable SSE and propose an extension for structured encryption under the active adversary setting. We first define verifiable structured encryption and its security under the notion of reliability similar to verifiable SSE, but with difference on how a tag for verifiability is defined. This is mainly due to the notions of semi-private data that does not exist in a verifiable SSE scheme. We then present constructions secure under this model and prove security of the constructions.